Sealing arrangement of a battery filling port using a rivet

Abstract

A sealed battery includes a filling hole, and a gasket and a blind rivet that seal the filling hole. A tapered surface that is inclined toward an inside of a battery case is formed around the filling hole of the battery case. The filling hole is sealed by the gasket and the blind rivet by the blind rivet plastic deforming.

The invention claimed is: 
     
       1. A sealed battery comprising:
 a battery case comprising a cover portion with an open through-hole; 
 a plug member that plugs the through-hole; and 
 a seal member that is an elastic body that seals between the through-hole and the plug member, wherein 
 the plug member is a blind rivet that includes a flange formed with a diameter larger than a diameter of the through-hole, and a sleeve formed with a diameter smaller than the diameter of the through-hole; 
 a tapered surface that is inclined toward an inside of the battery case is formed on a peripheral portion of the through-hole of an outside surface of the battery case, the tapered surface being inclined at the same angle throughout the tapered surface from a level portion of the cover portion to an inner wall surface of the through-hole, the inner wall surface extending parallel to the axial direction of the through-hole; and 
 the seal member is sandwiched between the flange and the tapered surface, and the through-hole is sealed by the flange, by a portion of the sleeve that is inserted into the inside of the battery case being plastic deformed so as to bulge out. 
 
     
     
       2. The sealed battery according to  claim 1 , wherein the through-hole is a filling hole for filling electrolyte. 
     
     
       3. The sealed battery according to  claim 1 , wherein the tapered surface of the peripheral portion of the through-hole that is formed on the outside surface of the battery case is formed only on the outside surface of the battery case. 
     
     
       4. The sealed battery according to  claim 1 , wherein the flange includes a surface that opposes the through-hole and is inclined toward the battery case from a radial outside of the flange toward a radial inside of the flange. 
     
     
       5. The sealed battery according to  claim 1 , wherein the flange includes a surface that opposes the through-hole and is inclined away from the battery case from a radial outside of the flange toward a radial inside of the flange. 
     
     
       6. The sealed battery according to  claim 1 , wherein the seal member is formed in a shape that matches a shape between the tapered surface and a surface of the flange that opposes the through-hole when the through-hole is sealed by the flange. 
     
     
       7. The sealed battery according to  claim 1 , wherein a protruding portion is formed on at least one of the tapered surface and a surface of the flange that opposes the through-hole.